Application of bridging-law concepts to short-fibre composites 4. FEM analysis of notched tensile specimens

This is the fourth paper in a series of four where notch sensitivities, fracture energies and bridging laws in short-fibre polymer composites are investigated. In this paper finite-element modelling (FEM) of centre-hole-notched tensile specimens is performed, with different bridging laws governing crack growth. Crack lengths, crack profiles and stress distributions are predicted. The results are compared with experimentally determined crack shapes from an earlier investigation. Only with softening bridging laws can the experimental results be matched. The predicted crack lengths are sensitive to bridging-law parameters. When bridging laws determined by the double cantilever beam (DCB) method are applied, the predicted crack lengths and profiles show good correlation with the experimental results. The results support the validity of the DCB method to determine bridging laws in short-fibre composites.